Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

CO2 effects on plants increases global warming

04.05.2010
Trees and other plants help keep the planet cool, but rising levels of carbon dioxide in the atmosphere are turning down this global air conditioner.

According to a new study by researchers at the Carnegie Institution for Science, in some regions more than a quarter of the warming from increased carbon dioxide is due to its direct impact on vegetation.

This warming is in addition to carbon dioxide's better-known effect as a heat-trapping greenhouse gas. For scientists trying to predict global climate change in the coming century, the study underscores the importance of including plants in their climate models.

"Plants have a very complex and diverse influence on the climate system," says study co-author Ken Caldeira of Carnegie's Department of Global Ecology. "Plants take carbon dioxide out of the atmosphere, but they also have other effects, such as changing the amount of evaporation from the land surface. It's impossible to make good climate predictions without taking all of these factors into account."

Plants give off water through tiny pores in their leaves, a process called evapotranspiration that cools the plant, just as perspiration cools our bodies. On a hot day, a tree can release tens of gallons of water into the air, acting as a natural air conditioner for its surroundings. The plants absorb carbon dioxide for photosynthesis through the same pores (called stomata). But when carbon dioxide levels are high, the leaf pores shrink. This causes less water to be released, diminishing the tree's cooling power.

The warming effects of carbon dioxide as a greenhouse gas have been known for a long time, says Caldeira. But he and fellow Carnegie scientist Long Cao were concerned that it is not as widely recognized that carbon dioxide also warms our planet by its direct effects on plants. Previous work by Carnegie's Chris Field and Joe Berry had indicated that the effects were important. "There is no longer any doubt that carbon dioxide decreases evaporative cooling by plants and that this decreased cooling adds to global warming," says Cao. "This effect would cause significant warming even if carbon dioxide were not a greenhouse gas."

In their model, the researchers doubled the concentration of atmospheric carbon dioxide and recorded the magnitude and geographic pattern of warming from different factors. They found that, averaged over the entire globe, the evapotranspiration effects of plants account for 16% of warming of the land surface, with greenhouse effects accounting for the rest. But in some regions, such as parts of North America and eastern Asia, it can be more than 25% of the total warming. "If we think of a doubling of carbon dioxide as causing about four degrees of warming, in many places three of those degrees are coming from the effect of carbon dioxide in the atmosphere, and one is coming from the direct effect of carbon dioxide on plants."

The researchers also found that their model predicted that high carbon dioxide will increase the runoff from the land surface in most areas, because more water from precipitation bypasses the plant cooling system and flows directly to rivers and streams. Earlier models based on greenhouse effects of carbon dioxide had also predicted higher runoff, but the new research predicts that changes in evapotranspiration due to high carbon dioxide could have an even stronger impact on water resources than those models predict.

"These results really show that how plants respond to carbon dioxide is very important for making good climate predictions," says Caldeira. "So if we want to improve climate predictions, we need to improve the representation of land plants in the climate models. More broadly, it shows that the kind of vegetation that's on the surface of our planet and what that vegetation is doing is very important in determining our climate. We need to take great care in considering what kind of changes we make to forests and other ecosystems, because they are likely to have important climate consequences."

The study is published in the May 3-7 online edition of the Proceedings of the National Academy of Sciences.

The Carnegie Institution (www.carnegiescience.edu) has been a pioneering force in basic scientific research since 1902. It is a private, nonprofit organization with six research departments throughout the U.S. Carnegie scientists are leaders in plant biology, developmental biology, astronomy, materials science, global ecology, and Earth and planetary science. The Department of Global Ecology, located in Stanford, California, was established in 2002 to help build the scientific foundations for a sustainable future. Its scientists conduct basic research on a wide range of large-scale environmental issues, including climate change, ocean acidification, biological invasions, and changes in biodiversity.

Ken Caldeira | EurekAlert!
Further information:
http://www.ciw.edu
http://www.carnegiescience.edu

More articles from Ecology, The Environment and Conservation:

nachricht Successful calculation of human and natural influence on cloud formation
04.11.2016 | Goethe-Universität Frankfurt am Main

nachricht Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

NTU scientists build new ultrasound device using 3-D printing technology

07.12.2016 | Health and Medicine

The balancing act: An enzyme that links endocytosis to membrane recycling

07.12.2016 | Life Sciences

How to turn white fat brown

07.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>